Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging.

Ahmed Abdelghfar,Noha Gaber,Noha Anous,Bassant M Fouad,Ahmed H Saad,Mohamed A Mousa

doi:10.3390/mi12070767

Ahmed Abdelghfar, Noha Gaber + Show 4 more

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https://doi.org/10.3390/mi12070767

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Abstract

Hyperspectral imaging has a wide range of uses, from medical diagnostics to crop monitoring; however, conventional hyperspectral imaging systems are relatively slow, bulky, and rather costly. In this paper, we present an inexpensive, compact tunable optical filter for hyperspectral applications. The filter is based on a Fabry-Pérot interferometer utilizing hybrid metallic-dielectric mirrors and actuated using a MEMS electrostatic actuator. The optical filter is designed using the transfer matrix method; then, the results were verified by an electromagnetic wave simulator. The actuator is based on a ring-shaped parallel plate capacitor and is designed using COMSOL Multiphysics. An actuation displacement of 170 nm was used, which is the required distance to tune the filter over the whole visible range (400–700 nm). There are two designs proposed for the optical filter: the first was optimized to provide maximum transmission and the other is optimized to have minimum full-width-half-maximum (FWHM) value. The first design has a maximum transmission percentage of 94.45% and a minimum transmission of 86.34%; while the minimum FWHM design had an average FWHM value of 7.267 nm. The results showed improvements over the current commercial filters both in transmission and in bandwidth.

Highlights

Since the development of hyperspectral imaging, the technology has proven to be useful in many applications
This captures spectral information that cannot be acquired by a color camera alone [2,3]. Such information enables the detection and classification of material properties throughout its spectral fingerprint [4]. This allows hyperspectral imaging to be utilized in many applications such as medical diagnostics [1,5], food and water quality check [6,7], agriculture crop monitoring [8,9], archaeology [10,11], and astronomy [12,13]
We present electrostatically actuated tunable filters for hyperspectral imaging systems

Summary

Introduction

Since the development of hyperspectral imaging, the technology has proven to be useful in many applications. The cube is formed by imaging the spatial dimensions at different spectral bands, forming a contiguous spectrum of spatial-spectral information about the scanned object. This captures spectral information that cannot be acquired by a color camera alone [2,3]. Such information enables the detection and classification of material properties throughout its spectral fingerprint [4] This allows hyperspectral imaging to be utilized in many applications such as medical diagnostics [1,5], food and water quality check [6,7], agriculture crop monitoring [8,9], archaeology [10,11], and astronomy [12,13]

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